Automatically optimizes your pages to minimize the number of network connections and ensure even third party resources won't slow down page rendering.
https://www.cloudflare.com/features-optimizer
Analytics and Tracking · Application Performance
Get access to data on 439,682 websites that are Cloudflare Rocket Loader Customers. We know of 33,892 live websites using Cloudflare Rocket Loader and an additional 405,790 sites that used Cloudflare Rocket Loader historically and 16,527 websites in the United States.
Get a list of 439,682 websites using Cloudflare Rocket Loader which includes location information, hosting data, contact details, 33,892 currently live websites and an additional 16,395 domains that redirect to sites in this list. 405,790 sites that used this technology previously and 16,527 websites in the United States currently using Cloudflare Rocket Loader.